9514 1404 393
Answer:
t = 0.49, 11.91
Step-by-step explanation:
A graphing calculator can show you the answers quickly. The times are 0.49 seconds and 11.91 seconds.
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We can write the equation as ...
h = 29
62t -5t^2 = 29 . . . . . substitute for h
-5(t^2 -12.4t) = 29
-5(t^2 -12.4t +6.2^2) = 29 -5(6.2^2) . . . . complete the square
-5(t -6.2)^2 = -163.2 . . . . . simplify
t -6.2 = ±√(-163.2/-5) = ±√32.64 . . . . divide by -5, take the square root
t = 6.2 ±5.71
t = 0.49, 11.91
The rocket has a height of 29 meters at t=0.49 seconds and t=11.91 seconds.
